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United States Patent |
6,039,476
|
Katagiri
,   et al.
|
March 21, 2000
|
Drive force transmission mechanism having inclined drive shaft for camera
Abstract
Drive force transmission device for a camera, namely, a film drive
mechanism for a camera, in which a drive force of a motor is transmitted
through a differential gear mechanism to a wind shaft and a rewind shaft
and is also transmitted through a screw gear to a spool shaft or a fork
shaft whereby operations of winding and rewinding film are performed. The
rewind shaft is placed in such a manner as to be inclined to the drive
shaft of the differential gear mechanism. Moreover, a fork shaft and a
spool shaft to be driven by film at the time of winding or rewinding the
film can be driven even when the screw gear and the helical gear remain
engaged with each other. This film drive mechanism occupies only a small
space and is small in weight and is advantageous for the cost thereof.
Inventors:
|
Katagiri; Moriya (Tokyo, JP);
Sugita; Yukihiko (Kokubunji, JP);
Kitahara; Yoshiyuki (Tokyo, JP)
|
Assignee:
|
Olympus Optical Co., Ltd. (Tokyo, JP)
|
Appl. No.:
|
927612 |
Filed:
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September 11, 1997 |
Foreign Application Priority Data
| Sep 13, 1996[JP] | H8-243547 |
Current U.S. Class: |
396/418 |
Intern'l Class: |
G03B 001/00 |
Field of Search: |
396/387,411,413,418
|
References Cited
U.S. Patent Documents
4304480 | Dec., 1981 | Fukahori et al. | 396/418.
|
4351595 | Sep., 1982 | Date et al. | 396/418.
|
5337108 | Aug., 1994 | Kaihara et al. | 396/387.
|
Foreign Patent Documents |
6-347876 | Dec., 1994 | JP.
| |
7-43801 | Feb., 1995 | JP.
| |
8-304894 | Nov., 1996 | JP.
| |
Primary Examiner: Blankenship; Howard B.
Attorney, Agent or Firm: Weinstein; Louis
Claims
What is claimed is:
1. A camera having a drive force transmission device, said device
comprising:
a plurality of drive shafts placed in a non-linear manner;
input gears, respectively provided on said plurality of drive shafts;
output gears, respectively provided on said plurality of drive shafts, for
outputting an input drive force applied to its associated input gear;
said plurality of drive shafts each lying in a different plane such that
said different planes are parallel with one another, said plurality of
drive shafts being respectively arranged in said planes which are nearly
parallel with one surface of said camera; and
drive force switching means for selectively coupling a drive force
transmitted from a drive source wherein said drive force switching means
has a gear which is operative to output a drive force to said input gears
and which has an axis of rotation that is inclined at a predetermined
angle to an axis of rotation of each of said input gears.
2. A camera having a film cartridge and a drive force transmission device,
said camera comprising:
a film cartridge compartment and a film wind-up chamber arranged on
opposite sides of an optical axis;
a plurality of drive shafts placed in a non-liner manner;
input gears, respectively provided on said plurality of drive shafts;
output gears, respectively provided on said plurality of drive shafts, for
outputting an input drive force applied to its associated input gear;
said plurality of drive shafts each lying in in a different plane such that
said different planes are nearly parallel with one another, said plurality
of drive shafts being respectively arranged in said different planes, one
of said planes being parallel with and another of said planes being nearly
parallel with one surface of said camera and said drive shafts being
respectively parallel and nearly parallel with a direction of movement of
film in said camera from said cartridge in the film cartridge compartment
to the wind-up chamber; and
drive force switching means for selectively coupling a drive force
transmitted from a drive source.
3. The drive force transmission device for a camera, according to claim 2,
wherein said output gears respectively provided on said plurality of drive
shafts are worms.
4. The drive force transmission device for a camera, according to claim 2,
wherein said input gears respectively provided on said plurality of drive
shafts are spur gears, and wherein said output gears respectively provided
on said plurality of drive shafts are worm gears.
5. The drive force transmission device for a camera, according to claim 2,
wherein said drive force switching means includes a differential gear
mechanism.
6. A drive force transmission device for a camera, comprising:
a first drive shaft for transmitting a drive force to a wind means;
a second drive shaft for transmitting a drive force to a rewind means, said
first and second drive shafts being placed in a non-linear manner so that
one of said first and second drive shafts is inclined at an angle relative
to another one of said first and second drive shafts;
first and second input gears respectively provided on said first and second
drive shafts;
a coupling gear;
a drive source for providing a drive force to said coupling gear;
drive force switching means for selectively moving said coupling gear
between a position for applying said drive force to said first input gear
and a position for applying said drive force to said second input gear;
and
output gears, respectively provided on said first and second drive shafts,
for outputting a drive force, which is inputted to the input gear selected
by said drive force switching means, to said wind means or said rewind
means.
7. The drive force transmission device for a camera, according to claim 6,
wherein said first and second drive shafts lie in a plane which is almost
parallel with a bottom surface of said camera.
8. The drive force transmission device of claim 6 wherein the wind means
includes a driven gear and the rewind means includes a driven gear and
said driven gears are screw gears and the output gears on the first and
second shafts are worms.
9. The drive force transmission device of claim 6 wherein said input gears
are each mounted near one end of their respective drive shaft and said
output gears are each mounted near an opposite end of their respective
drive shaft; and
the end of one of said first and second drive shafts having an output gear
being closer to a bottom surface of said camera than the end of said one
of said first and second drive shafts having an input gear.
10. The drive force transmission device of claim 6 wherein an axis of
rotation of one of said first and second shafts having an output gear is
inclined at an angle on the order of 2 degrees relative to an axis of
rotation of said coupling gear.
11. The drive force transmission device of claim 6 wherein an axis of
rotation of one of said shafts having an output gear is inclined at an
angle on the order of 2 degrees relative to an axis of rotation of said
coupling gear and an axis of rotation of a remaining one of said shafts
having an output gear is substantially parallel to the axis of rotation of
said coupling gear.
12. A drive force transmission device for a camera, comprising:
first and second drive shafts placed in a non-linear manner so that one of
said first and second drive shafts is inclined at an angle relative to
another one of said first and second drive shafts, said first and second
drive shafts respectively having gears adapted to output a drive force,
which is transmitted from a drive source, to wind means or rewind means;
and input gears respectively provided on said first and second drive
shafts, a drive force transmitted from said drive source being selectively
coupling to said input gears by a drive force switching mechanism.
13. The drive force transmission device for a camera, according to claim
12, wherein said first and second drive shafts are respectively provided
to lie in planes which are nearly parallel with a bottom surface of said
camera.
14. The drive force transmission device for a camera, according to claim
12, wherein said output gears are worms.
15. A drive force transmission device for a camera, comprising:
a first drive shaft provided with a first input gear near a first end of
the first drive shaft and a first output gear near a second end of said
first drive shaft;
a second drive shaft arranged substantially in parallel with said first
drive shaft and provided with a second input gear near a first end of the
second drive shaft and a second output gear near a second end of said
second drive shaft, said second input gear being positioned near said
first input gear on said first drive shaft and said second output gear
being remote from said first output gear on said first drive shaft, said
second drive shaft extending in a first direction from said second input
gear toward said second output gear which is opposite and away from a
direction of said first shaft which extends in a second direction from
said first input gear toward said first output gear, so that the distance
between the first and second output gears is greater than a distance
between said first and second input gears;
a drive source;
a driving gear for receiving a drive force from said drive source; and
drive force switching means for selectively moving said driving gear
between first and second positions to respectively couple the drive force
to said first and second input gears.
16. A drive transmission device for a camera according to claim 15, wherein
said first and second drive shafts respectively lie in planes which are
nearly parallel with a bottom surface of said camera.
17. A drive force transmission device for a camera, comprising:
a first drive shaft provided with a first input gear and a first output
gear;
a second drive shaft provided substantially in parallel with said first
drive shaft and provided with a second input gear and a second output
gear, said second input gear being positioned near said first gear on said
first shaft and said second output gear being remote from said first
output gear on said first drive shaft, a distance between the output gears
being greater than a distance between said input gears;
a driven source;
a driving gear for receiving a drive force from said drive source; and
drive force switching means for selectively moving said driving gear
between first and second positions to respectively couple the drive force
to said first and second input gears said driving gear which is operated
by said drive force switching means to output a drive force to one of said
input gears, having an axis of rotation that is inclined at a
predetermined angle to an axis of rotation of each of said input gears.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a drive force transmission device for
driving a driven portion of a camera.
2. Description of the Related Art
A conventional drive force transmission device for a camera, which has been
previously proposed in Japanese Unexamined Patent Publication No. 8-304894
Official Gazette, is intended for use in a camera incorporating a drive
mechanism adapted to select and drive a plurality of driven systems. In
the aforementioned camera, a drive force from a drive source is
selectively transmitted to winding means or rewinding means through a
drive mechanism constituted by a plurality of connected gears.
However, in the case of the aforesaid conventional drive force transmission
device disclosed in Japanese Unexamined Patent Publication No. 8-304894
Official Gazette, it is necessary for transmitting to place a plurality of
gear transmission systems constituted by spur gears therein. Thus,
necessary space increases, so that it is inevitable to increase camera
size. Moreover, when reducing the sizes of the gears so as to downsize the
camera, the transmission efficiency of the device is degraded. Further,
the number of parts or components increases. Thus, such a camera is
disadvantageous due to the cost thereof. Therefore, the conventional drive
force transmission device has encountered such serious problems in
optimization of gear placement.
Hitherto, power transmission through a gear train composed of spur gears
has been generally used. However, in the case that there are a plurality
of transmission paths which are long, there are too many gears to be
contained in a camera. Consequently, the conventional drive force
transmission device has a disadvantage that the transmission efficiency is
deteriorated.
Further, conventional drive force transmission devices for cameras, which
have been previously proposed in Japanese Unexamined Patent Publication
Nos. 6-347876 and 7-43801 Official Gazettes, respectively, are intended
for use in film feeders of cameras. Thus, the lead angles of helical gears
of the drive force transmission system are set at predetermined values,
respectively. Moreover, it is realized that both a spool gear and a
winding gear for film are driven according to the magnitude of the drive
force from the drive source, alternatively, the spool gear and the winding
gear are selectively driven according thereto.
However, the aforementioned drive force transmission devices disclosed in
Japanese Unexamined Patent Publication Nos. 6-347876 and 7-43801 Official
Gazettes, respectively, employ a mechanism in which two rotary shafts are
coupled to each other or uncoupled from each other in a line. Thus, the
conventional drive force transmission devices have an inconvenience in
that a space, in which the rotary shafts move, is needed, and that
furthermore, the lateral size of the camera is increased. Moreover, the
helical gear should be designed so that two rotary shafts are coupled or
uncoupled in a line. Additionally, two rotary shafts are coupled and
uncoupled. Therefore, it is necessary to enhance the accuracy of the
helical gear and a gear to be engaged therewith. Furthermore, it is
necessary for preventing the degradation in transmission efficiency to
enhance the accuracy of each coupling portion for coupling the two rotary
shafts. Consequently, the conventional drive force transmission device is
disadvantageous due to the cost thereof.
SUMMARY AND OBJECT OF THE INVENTION
The present invention is accomplished in view of the aforementioned
problems of the conventional drive force transmission device.
Accordingly, an object of the present invention is to provide a drive force
transmission device for a camera, which is compact and has a small
occupied space, without deteriorating the transmission efficiency thereof.
To achieve the foregoing object, in accordance with an aspect of the
present invention, there is provided a drive force transmission device for
a camera, by which a drive force is transmitted from a drive source to a
plurality of drive mechanisms such as a film drive unit and a lens drive
mechanism of the camera. This drive force transmission device comprises:
input-side gears each rotated by a drive force transmitted from the
aforesaid drive source; output-side gears each for driving the aforesaid
drive unit; a plurality of drive shafts for transmitting a rotation of the
aforesaid input-side gear to the aforesaid output-side gear; and drive
force switching means for changing the input-side gear to which a drive
force is transmitted.
In the case of an embodiment of the aforesaid drive force transmission
device for a camera according to the present invention, a plurality of
drive shafts are provided on an almost flat surface of a bottom portion of
the camera in such a manner as to extend nearly in parallel with a film
feeding direction.
Other features, objects and advantages of the present invention will become
apparent from the following description of a preferred embodiment with
reference to the accompanying drawings in which like reference characters
designate like or corresponding parts throughout several views.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a drive mechanism that is a drive
force transmission device for a camera, which is an embodiment of the
present invention;
FIG. 2 is a schematic longitudinal sectional view of the drive force
transmission device for a camera of FIG. 1;
FIG. 3 is a schematic sectional view of a planetary gear mechanism of the
drive mechanism of the camera of FIG. 1 and surroundings thereof;
FIG. 4 is a perspective view of a differential gear mechanism and a film
feeding mechanism portion of the drive mechanism of the camera of FIG. 1;
FIG. 5 is another perspective view of the differential gear mechanism and
the film feeding mechanism portion of the drive mechanism of the camera of
FIG. 1, which illustrates a state in which a wind drive mechanism is
driven;
FIG. 6 is another perspective view of the differential gear mechanism and
the film feeding mechanism portion of the drive mechanism of the camera of
FIG. 1, which illustrates a state in which a rewind drive mechanism is
driven;
FIG. 7 is an exploded perspective view of the film feeding mechanism
portion of the drive mechanism of the camera of FIG. 1, which is viewed
from the bottom of the body of the camera;
FIG. 8 is a schematic circuit diagram of an electric control circuit of the
camera to which the drive mechanism of FIG. 1 is applied;
FIG. 9 is a flowchart of a program for performing a sequence of steps of a
photographing process of the camera to which the drive mechanism of FIG. 1
is applied;
FIG. 10 is a flowchart of a subroutine for performing a film rewinding
operation, which is called in the photographing process; and
FIG. 11 is a flowchart of a subroutine for performing a film-end detecting
operation, to be called by another subroutine for performing a one-frame
advance operation, which is called in the photographing process of FIG. 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Hereinafter, the preferred embodiment of the present invention will be
described in detail by referring to the accompanying drawings.
FIG. 1 is an exploded perspective view of a drive mechanism that is a drive
force transmission device for a camera, which is an embodiment of the
present invention. FIG. 2 is a schematic longitudinal sectional view of
the aforesaid drive force transmission device for a camera. FIG. 3 is a
schematic sectional view of a planetary gear mechanism of the aforesaid
drive mechanism of the camera and surroundings thereof, which is taken in
the direction of a drive shaft thereof. Further, FIGS. 4 to 6 are
perspective diagrams for illustrating working conditions of a film feeding
mechanism portion and surroundings thereof. FIG. 7 is an exploded
perspective view of the film feeding mechanism portion and surroundings
thereof, which is taken from the bottom of the body of the camera.
Incidentally, in the aforesaid FIGS. 4 to 6, the body of the camera and an
end plate, which is a cover for a gear portion, are not shown for
simplicity.
As illustrated in FIGS. 1 and 2, the drive mechanism of this embodiment of
the present invention is provided mainly with: a motor portion containing
a motor 1 which serves as a drive source; a differential gear mechanism
21, which is driven by the aforesaid motor 1 and has two output gears; and
a drive mechanism 23 (see FIG. 2) for driving a drive gear train, which
includes an idle gear 9 (shown in block diagram form) acting as a first
driven system to be driven by one of the output gears, and for driving a
lens-barrel. Further, the aforementioned drive mechanism is provided with:
a film feeding mechanism consisting of a film wind drive mechanism 25 and
a film rewind drive mechanism 26, which serve as a second driven system
driven by the other of the output gears; a planetary gear mechanism 22 for
selecting a driven system to be driven by the aforementioned differential
gear mechanism 21; a shutter mechanism 24 (see FIG. 2) serving as a third
driven system which is different from the first and second driven systems;
and a plunger unit 27 acting as an electromagnetic drive source for
switching a driven system, to which power is transmitted, and for driving
the aforesaid third driven system; and a clutch lever 20 to be driven by
the aforesaid plunger unit 27.
A camera incorporating the aforesaid drive mechanisms is provided with: a
camera body 57 on the left and right sides of which a film cartridge
chamber 57a and a spool chamber 57b are placed as viewed in FIG. 1; and a
front panel or plate 56 which is mounted in the central portion of the
aforesaid camera body 57 and has a lens-barrel mounting aperture portion
56c.
Further, the aforesaid film feeding mechanism portion is disposed at a
lower part of the aforementioned camera body 57. Moreover, the motor 1 and
the plunger unit 27 are disposed at a lower part of the front panel 56.
Furthermore, a differential gear mechanism 21 and a planet gear mechanism
22 are similarly disposed at the aforesaid lower part. Additionally, a
lens barrel 34 containing a built-in shutter mechanism 24, and a
lens-barrel drive mechanism 23, which are mounted in the aperture portion
56c, are incorporated into the front panel 56 (see FIG. 2).
Hereinafter, the configuration of each of the aforesaid elements will be
described. First, the motor 1 composing the aforementioned motor portion
is a rotary drive source, and output shafts respectively project from
opposite end surfaces of the motor 1. Slit disk 1b, in which holes
allowing light to pass therethrough and faces being operative to cut off
light are consecutively arranged along the circumference thereof, is
securely fixed at an end part of one of the output shafts so as to control
rotation of this motor 1. Further, a photointerrupter 61, in which a light
projecting element and a light receiving element are disposed as a unit,
is placed in such a manner as to sandwich this slit disk 1b. Then, the
aforementioned photointerrupter 61 outputs a pulse signal corresponding to
an angle of rotation of the motor.
Moreover, a pinion 1a is fixedly mounted at the other output shaft end of
the motor 1. This pinion 1a engages with a plurality of planetary gears 4,
for example, three planetary gears 4 of the differential gear mechanism 21
(to be described later).
The aforesaid differential gear mechanism 21 is composed of: carriers 2 and
5, which have three planetary gears 4 and 6 as two stage planetary gear
mechanisms, respectively; a gear 3 consisting of an internal gear portion
3a and an external gear portion 3b; and an end plate 7 which is fixed to
the front panel 56 and contains an internal gear 7a and an internal sector
gear 7b and is used as a cover for the aforementioned gear mechanism as
illustrated mainly in FIGS. 1 and 2.
The aforesaid planetary gears 4 are rotatably supported by a plurality of
shafts 2a in the carrier 2 having a rotating gear 2b, respectively, and
can rotate around each of such shafts 2a. Moreover, the aforesaid
planetary gear 4 further engages with the internal gear portion 3a of the
rotatable gear 3. External gear portion 3b of this gear 3 is coupled to a
bevel gear 31 for driving the lens-barrel drive mechanism 23 (to be
described later) through a gear train composed of an idle gear 9, a spur
gear 10a and a bevel gear 10b of the gear 10.
Incidentally, the aforesaid idle gear 9 is supported by a shaft portion 56b
of the camera front panel 56. Further, the aforesaid gear 10 is supported
on a shaft 56a which is eccentric to the shaft portion 56b. The aforesaid
gear 2b of the carrier 2 further engages with the three planetary gears 6
each of the carrier 5. These planetary gears 6 are supported on a shaft 5a
for rotation, which is provided in the carrier 5 that is similar to the
carrier 2. These planetary gears 6 respectively engage with an internal
gear 7a provided in the end plate 7 that is fixed in the camera body. The
aforesaid carrier 5 further has a gear portion 5b acting as an output
gear. The gear portion 5b engages with a gear portion 12a of a gear 12 (to
be described later) through a gear train (not shown) and drives the
planetary gear mechanism 22.
It is assumed that the shaft center of the pinion 1a, the gear 3, the
carriers 2 and 5 and the internal gears 7a of the aforementioned motor 1
is placed on the output shaft of the motor 1. Further, an output of the
motor 1 is switched between outputs respectively corresponding to two
drive systems by using a clutch lever 20 and the aforesaid differential
gear mechanism 21. One of the outputs respectively corresponding to the
two drive mechanisms is a drive output to be used by the lens-barrel drive
mechanism 23 for driving the lens barrel in such a manner as to advance
and retreat, while the other of the outputs respectively corresponding to
the two drive mechanisms is a drive output to be used for driving the
planetary gear 14 of the planetary gear mechanism 22 and thus to be used
by the film feeding mechanism (to be described later).
The aforesaid lens-barrel driving mechanism 23 is operative to drive the
lens barrel 34, which holds photographing lens groups 35 and 36, to
advance along the optical axis O from a collapsing position P34A, which is
located in a non-photographing area, to a photographable position P34B,
which is located in a photographing area, as illustrated in FIG. 2.
Moreover, the lens-barrel drive mechanism 23 drives the lens barrel to
advance and retreat between the photographable positions P34B and P34C,
which are located in the photographing area, with the intention of
adjusting the focus of a lens.
The aforesaid lens-barrel drive mechanism 23 is composed mainly of: a bevel
gear 31 engaging with the bevel gear 10a of the aforesaid gear 10; a screw
shaft 32 for causing the lens barrel 34 of the camera to advance and
retreat along the optical axis O of the photographing lens; a guide shaft
33 which is slidably fitted into the lens barrel 34; a female screw 34a of
the lens barrel 34, which is screwed into the aforesaid screw shaft 32;
and an encoder portion for detecting the advanced and retreated positions
of the lens barrel.
Incidentally, the aforementioned bevel gear 31 is fixed to the aforesaid
screw 32 in such a manner as to be integral therewith. The guide shaft 33
is placed in parallel with the screw shaft 32 which is slidably fitted
into the lens barrel 34.
Further, the lens barrel 34 holds the photographing lens groups 35 and 36
and contains the shutter mechanism 24, as illustrated in FIG. 2.
The aforesaid shutter mechanism 24 consists of: what is called an arrow
wheel 37 serving as a drive member which is rotatable mainly about the
lens barrel; a sector 39 for opening and closing a shutter (namely,
performing exposure and shading) as the aforesaid arrow wheel rotates
clockwise or counterclockwise; and a spring 47 for pushing the sector 37
in an opening direction.
Incidentally, the aforesaid arrow wheel 37 has a rotation operation portion
38 whose edge portion can move from a shutter closing position P38A or
P38A' to a shutter opening position P38B by rotating.
The aforesaid arrow wheel 37 moves by advancing and retreating together
with the lens barrel 34. When the lens barrel 34 is located at the
collapsed position P34A as shown in FIG. 3, a camera-front-panel-side
stopper portion 56f acting as a limiting portion for holding the rotation
operation portion 38 of the aforesaid arrow wheel 37 at the shutter
closing position P38A is provided on a camera side. When the lens barrel
34 is advanced to a place between the photographable positions P34B and
P34C on the photographing area, the rotation operation portion 38 of the
arrow wheel 37 moves to the position P38A' whereupon the portion 38 is put
into a ready-for-release state and is further put into a rotatable state
in which the portion 38 can move to the shutter opening position P38B.
The aforesaid encoder portion is an encoder for detecting the position of
the lens barrel 34 itself. The encoder portion has an encoder circuit
board 43, which is provided with encoding patterns 43a, 43b and 43c, and a
sliding armature group 42 (constituted by a same conductive member), which
can make contact with the aforementioned patterns.
The aforesaid armature group 42 consists of three armatures as shown in
FIG. 2. First armature 42a thereof is always electrically in contact with
the common pattern 43a. When performing the focusing of the lens barrel
34, the second armature 42b makes contact with the count starting position
detection pattern 43b under sliding conditions so as to judge the advanced
position of the lens. The count starting point, at which the counting of
output pulse signals of the photointerrupter 61 is started, is detected
according to the detection pattern 43b.
Further, the third armature 42c makes contact with the collapsing detection
pattern 43c to be used for judging whether or not the lens barrel 34 is at
a collapsed position with respect to the camera. Incidentally, an actual
detection point detected according to the aforesaid second armature 42b is
a point at which a patterns to be used is changed between the patterns 43a
and 43b. Moreover, an actual detection point detected according to the
aforesaid second armature 42c is a point at which a patterns to be used is
changed between the patterns 43a and 43c.
The aforesaid planetary gear mechanism 22 is composed of: the gear portion
12a engaging the gear portion 5b of the carrier 5; a planetary gear arm
13; and a planetary gear 14 engaging a sun gear portion 12b. Incidentally,
the planetary gear arm 13 is rotatably supported on the shaft of the
aforesaid gear 12. Further, the planetary gear 14 is rotatably supported
on the shaft that is provided on the aforesaid planetary gear arm 13.
Therefore, the aforesaid planetary gear 14 can rotate on the axis thereof
and move around the shaft of the gear 12. The fixing internal sector gear
7b provided in the end plate 7, which is fixed to the camera body, and the
spur gear 8 supported on the supporting shaft 8a as a selected engaging
gear for a film rewinding drive operation (to be described later) and the
gear 19 supported on a winding shaft 50 as a selected engaging gear for
winding film (to be described later) are disposed on the locus of the
revolution of the planetary gear 14 around the shaft of the gear 12.
Further, the planetary gear 14 can be engaged with the aforesaid gears 7b,
8 and 19 by causing the planetary gear arm 13 to stop at rotation
positions P13A, P13B and P13C, respectively. The selection of the rotation
position, at which the planetary gear arm 13 is stopped, thereamong is
performed by the movement of the clutch lever 20 to be controlled by the
plunger unit 27 (to be described later).
Incidentally, a reflecting plate 13a for reflecting light is provided at an
edge portion that is opposite to the side on which the planetary gear 14
of the planetary gear arm 13 is located. Further, a photoreflector for a
clutch 62 is placed at a position where the aforesaid planetary gear 14
engages with the spur gear 8 (to be described later), and where the
photoreflector faces the aforesaid reflecting plate 13a.
As shown in FIGS. 1 to 3, the aforesaid plunger unit 27 is composed of: the
solenoid 27a; a moving core 27b which can be withdrawn or projected by
turning on or off the aforementioned solenoid 27a; and a return spring 27c
pushing the aforesaid core 27b in a projecting direction in which the core
27b is projected.
The aforesaid clutch lever 20 is illustrated in FIG. 3 as being in a
parallel displacement state. However, the clutch lever 20 is supported on
the camera body in such a manner as to be able to rotate in the supporting
shaft hole 20e. The position of the planetary gear arm 13 is controlled by
the rotation of the clutch lever 20.
Moreover, the clutch lever 20 is provided with arm portions 20a and 20b,
which goes into and out from the displacement plane of the planetary gear
arm 13 in a direction perpendicular thereto, as shown in FIG. 1.
Furthermore, an arm portion 20c, which goes into and out from the
arrow-wheel rotation operation portion 38 at an engaging position and at a
disengaging position, is provided in the aforesaid clutch lever 20.
Additionally, a connecting pin 20d, which is adapted to engage with a
groove 27d bored in the core 27b of the plunger unit 27, is provided in
the aforesaid clutch lever 20. The position of the clutch lever 20 is
controlled by the aforesaid plunger unit 27.
Namely, in a state in which the solenoid 27a of the plunger unit 27 is
turned off (i.e. deenergized), the aforesaid core 27b is protruded from
solenoid 27a, as shown in FIG. 3. Further, the clutch lever 20 is at an
engaging position P20A, and holds the planetary gear arm 13 by the arm
portion 20a thereof. Moreover, the planetary gear arm 13 is held by the
arm portion 20b of the clutch lever 20 at the position P13B.
Furthermore, when the lens barrel 34 is at the photographable position P34B
or P34C (see FIG. 2) and the clutch lever 20 is at the engaging position
P20A, the arrow wheel rotation operation portion 38 for opening and
closing the shutter is held at the shutter closing position P38A'.
Further, when the solenoid 27a is turned on (i.e. energized, and the
aforesaid core 27b is attracted thereto and the clutch lever 20 retreats
to an evacuation position, the aforesaid planetary gear arm 13 is able to
perform a rotating operation. Moreover, the arm portion 20c retreats.
Thus, if the rotation operation portion 38 for performing the rotation
operation of the arrow wheel 37 for opening and closing the shutter is at
the position P38A', the portion 38 moves to the shutter opening position
P38B. Consequently, an exposure operation is performed.
Incidentally, the aforesaid clutch lever 20 is pushed in a direction in
which the shutter mechanism 24 is closed by a closing spring 48 serving as
a pushing means and in which the core 27b is protruded. Further, although
the closing spring 48 and the return spring 27c are different from each
other only in an embodying manner, these springs have a similar function.
The aforesaid film wind drive mechanism 25 is composed of the winding shaft
50, which acts as a drive shaft, and a spool shaft 52, as illustrated in
perspective diagrams of FIGS. 4 to 6 or an exploded perspective diagram of
FIG. 7.
Incidentally, the gear 19, with which the aforementioned planetary gear
mechanism 22 and the planetary gear 14 can engage, and the screw gear (or
worm gear) 50a are rigidly fixed to the aforesaid winding shaft 50.
Further, the aforesaid spool shaft 52 has a driven bevel gear 52a, which
engages with the aforesaid screw gear 50a, and a fitting portion fitted
into a spool cylinder (namely, a take-up spool) 54 (see FIG. 7) for
winding film. Moreover, the aforesaid spool shaft 52 is rotatably
supported in the supporting shaft hole 57c of the camera body 57 and is
operative to support the spool cylinder 54.
Screw gear 50a is made of or metal or plastic. In the case that the screw
gear 50a is made of metal, it is preferable that an easy-to-process
material, such as a brass and a soft steel, is used and processed by
cutting and working and the surface of the screw gear is plated, for
instance, nickel-plated by using a lubricative surface modifier such as
Teflon (incidentally, "Teflon" is a registered trade mark). In the case
that the screw gear 50a is made of plastic, it is preferable to use a
resin made of a crystal of, for example, a polyacetal resin.
Under the load of the bevel gear 52a, the shaft of the screw gear 50a bends
away therefrom and undergoes a force in a direction in which the
engagement between the gears is reduced. When the shaft bends in this
manner, there are fears of a reduction in efficiency, an occurrence of
abnormal sound and a shortage of gear strength.
However, the aforementioned reduction in performance can be prevented by
employing the metallic screw gear 50a, without upsizing the device. In the
case that the screw gear 50a is made of plastic, the winding shaft 50 is
made of metal. Moreover, this shaft is fitted into and fixed to the screw
gear 50a. Thus, advantageous effects similar to those described above can
be obtained.
Similarly as in the case of the aforesaid screw gear 50a, the bevel gear
52a is made of metal or plastic. In this case, it is preferable that the
screw gear and the bevel gear 53a are different in material from each
other, because neither abrasion due to a bite by teeth of the gear nor
degradation in transmission efficiency are caused.
Thus, for the aforementioned reasons, it is preferable for obtaining a
drive force transmission device, which has sufficient performance in spite
of a small size thereof, to employ the screw gear 50a made of metal and
the bevel gear 52a made of plastic.
The aforesaid film rewind drive mechanism 26 is composed of the rewinding
shaft 51, which acts as a drive shaft, and a fork shaft 53, similarly as
illustrated in the perspective diagrams of FIGS. 4 to 6 or the exploded
perspective diagram of FIG. 7.
Incidentally, the spur gear 18 engaging the spur gear 8, with which the
aforementioned planetary gear mechanism 22 and the planetary gear 14 can
engage, and the screw gear (or worm gear) 51a are securely fixed to the
aforesaid rewinding shaft 50. Further, the aforesaid fork shaft 53 has a
driven bevel gear 53a, which engages with the aforesaid screw gear 51a,
and a fork portion 53b fitted into a spool of a film cartridge. Moreover,
the aforesaid fork shaft 53 is rotatably supported in the supporting shaft
hole 57d of the camera body 57 and is disposed on a cartridge chamber 57a.
Even in the case of the rewind drive mechanism, it is preferable to employ
the screw gear 51a made of metal and the bevel gear 53a made of plastic,
similarly as in the case of the aforesaid wind drive mechanism.
Further, as shown in the exploded perspective diagram of FIG. 7, which
illustrates the camera body 57 and is taken from below, the wind shaft 50
is fitted into shaft fitting portions 57e, 57f and 57g, which are provided
under the film cartridge chamber 57a and the spool chamber 57b.
Incidentally, a coating of grease is applied to the engaging surfaces of
the aforesaid shaft fitting portions 57e, 57f and 57g, the screw gear 50a
and the bevel gear 52a.
Furthermore, as illustrated in the aforementioned exploded perspective
diagram of FIG. 7, the rewind shaft 51 is fitted into the shaft fitting
portions 57h and 57i, which are provided under the film cartridge chamber
57a, and the shaft fitting portion 56j of the front panel 56.
Incidentally, a coating of grease is applied to the engaging surfaces of
the aforesaid shaft fitting portions 57h, 57i and 56j, the screw gear 51a
and the bevel gear 53a.
The aforesaid wind shaft 50 and the aforementioned rewind shaft 51, which
are fitted into a set of the shaft fitting portions 57e, 57f and 57g and
another set of the shaft fitting portions 57h, 57i and 56j, respectively,
are pressed by a metallic pressing plate 55 mounted on the camera body 57
by screwing, and thus are rotatably supported on the camera body 57 or the
front panel 56. Simultaneously, the aforesaid fork shaft 53 and the
aforementioned spool shaft 52 are rotatably supported on the camera body
57 during the time the shafts 52 and 53 are pressed by the aforesaid
pressing plate 55.
The aforesaid shafts 50 and 51 are put into a three-point suspension state
in the aforementioned shaft fitting portions, respectively. Thus, each of
the aforesaid shafts 50 and 51 is supported in a state in which a slight
clearance of small dimensions is present in the central shaft fitting
portion of the corresponding set.
Incidentally, the aforesaid rewinding shaft 51 is attached to the camera
body 57, as above described and as illustrated in the perspective diagram
of FIG. 4 or in the exploded perspective diagram of FIG. 7. The rewinding
shaft 51 is mounted therein in such a manner that the direction D51
thereof is inclined to a direction D2, which is parallel with the
direction of the shaft of the motor 1, so that an edge thereof, which is
provided on the side of the spur gear 18, is inclined upwardly as viewed
in FIG. 4 (namely, downwardly as viewed in FIG. 7 which is a perspective
diagram taken from below). Namely, the rewinding shaft 51 is mounted
therein in such a manner as to be inclined toward the center of the camera
body so that an angle .theta. of inclination is 2.degree. or so.
Additionally, the direction of the shaft of the motor 1 is set to be a
horizontal direction which is orthogonal to the optical axis O.
When mounting the rewinding shaft 51 therein in such a manner as to be
inclined in spite of the fact that the supporting shaft 8a of the spur
gear 8 serving as a selected engaging gear with which the spur gear 18 to
be fixed to the rewinding shaft 51 engages, the rewinding shaft 51 can be
mounted therein without problems by providing a backlash so that no
interference is caused in the closest region between the spur gears 18 and
8. Consequently, the aforesaid gear can be engaged therewith.
Incidentally, the engagement between the bevel gear 53a of the fork shaft
53 and the screw gear 51a causes no problems, because this is the
engagement thereof with a screw gear.
By mounting the rewinding shaft 51 therein in such a manner that an edge
thereof provided on the side of the spur gear 18 is inclined upwardly as
above described, the shaft end portion and a part of the spur gear 18 can
extend into the inside of the camera front panel 56. Consequently, the
space can be effectively utilized.
FIG. 5 illustrates a state of a film winding operation in which the winding
shaft 50 is driven. In this winding state, the screw gear 50a having a
right-hand thread is rotated clockwise as viewed in FIG. 4, as will be
described later. Thus the bevel gear 52a engaging with this screw gear 50a
is rotated clockwise as viewed in FIG. 4, so that the film is wound up. At
that time, the winding shaft 50 is moved rightwardly by a thrust of the
screw gear, as viewed in FIG. 4. Upper right end portion of the winding
shaft 50, which is illustrated in an upper right portion in FIG. 4, is
shaped like a hemi-sphere and abuts against a leading-edge portion (not
shown) of the pressing plate. A coating of grease is applied to this
abutting portion to be abutted.
During the aforesaid winding operation, the fork shaft 53 of the cartridge
chamber undergoes clockwise torque. This torque causes the rewinding shaft
51 to move leftwardly and downwardly as viewed in FIG. 4. Lower left end
portion of the rewinding shaft 51, which is illustrated in FIG. 4, is
shaped like a hemi-sphere and abuts against an edge part of the fitting
portion 57h of the camera body 57. A coating of grease is applied to this
abutting part to be abutted.
In the case of this film drive mechanism, the bevel gear 53a of the fork
shaft 53 and the screw gear 51a of the rewinding shaft 51 have simpler
structures and remain engaged. However, it is generally difficult to
rotate the screw gear 51a of the rewinding shaft, whose helix angle is
large, by the bevel gear 53a.
Thus, in the case of the film drive mechanism of this embodiment, the axial
abutting portion of the rewinding shaft 51 is shaped like a hemi-sphere,
as described above. Further, this abutting portion is caused to make
point-contact at the center of rotation. Consequently, a rotational load
is reduced. Further, the screw gear 51a, which remains engaged, can be
rotated smoothly by employing the specifications of the gear, by which the
helix angle of the screw gear is set as being not more than 70.degree. as
described in TABLE 1 listed below. Incidentally, the transmission
efficiency of the screw gear has a maximum value in the vicinity of a
helix angle of 60.degree.. Therefore, it is preferable that the helix
angle is set at a value which is not more than 70.degree. but is in the
proximity of 60.degree..
The perspective diagram of FIG. 6 illustrates a state of a film rewinding
operation in which the rewinding shaft 51 is driven. During the rewinding
operation, the spool shaft 52 of the spool chamber undergoes
counterclockwise torque. Similarly as in the case of the screw gear 51a,
it is difficult to rotate the screw gear 50a of the rewinding shaft, whose
helix angle is large, by the bevel gear 52a. Thus, in the case of the film
drive mechanism of this embodiment, the rewinding shaft 51 has a structure
similar to that of the aforesaid winding shaft 50. Moreover, the
specifications of the gear described in TABLE 2 listed below are employed.
Consequently, the screw gear 50a, which remains engaged, can be rotated
smoothly.
TABLE 1
______________________________________
Screw Gear 51a
Bevel Gear 53a
Classification Pinion Gear
______________________________________
Tooth Tooth Form Full Depth Tooth
Module 0.3
Pressure Angle
20.degree.
Number of Teeth 2 43
Shaft Angle 87.71.degree.
Helix Angle 65.degree. 22.71.degree.
Helix Direction Right-Hand
Reference Pitch Diameter
.phi.1.42 .phi.13.98
Normal Addendum +0.4 -0.25
Modification Coefficient
Amount of Addendum
+0.12 -0.75
Modification
Center Distance 7.9 mm
______________________________________
TABLE 2
______________________________________
Screw Gear 51a
Bevel Gear 53a
Classification Pinion Gear
______________________________________
Tooth Tooth Form Full Depth Tooth
Module 0.3
Pressure Angle
20.degree.
Number of Teeth 2 24
Shaft Angle 90.degree.
Helix Angle 66.degree. 24.degree.
Helix Direction Right-Hand
Reference Pitch Diameter
.phi.1.475 .phi.7.881
Normal Addendum +0.5 +0.2
Modification Coefficient
Amount of Addendum
+0.15 -0.06
Modification
Center Distance 4.9 mm
______________________________________
In the case that power transmission is performed by arranging spur gears
similarly as in the case of the conventional device, the transmission
efficiency is degraded when the number of the spur gears is increased.
Therefore, it is necessary to decrease the number of the gears as much as
possible. To that end, the diameter of the gear should be increased. Thus,
a large space is required to dispose a plurality of power transmission
systems in the device. Consequently, the downsizing of a camera is
hindered.
On the other hand, in the case of the film drive unit which is a drive
force transmission device according to this embodiment, a plurality of
power transmission systems between the winding shaft 50 and the rewinding
shaft 51 are disposed in the bottom portion of the camera in such a manner
as to be nearly parallel with one another, as illustrated in the
perspective diagrams of FIGS. 4 to 6 and the exploded perspective diagram
of FIG. 7. Therefore, differently from the case of performing power
transmission by arranging spur gears, neither the cost of the device is
increased, nor the efficiency thereof is degraded in the case that the
power transmission is performed by using the drive shafts such as the
winding shaft and the rewinding shaft. This is because the number of
members is not increased regardless of the distance, for which power
should be transmitted, in the latter case. Additionally, a plurality of
power transmission systems can be disposed in a small space.
Next, each operation of the drive force transmission mechanism of this
embodiment having the aforementioned configuration will be described
hereinbelow by first beginning with the description of advancing and
retreating operations of the lens barrel.
When the sun gear portion 12b of the aforesaid gear 12 is rotated clockwise
as viewed in FIG. 3 by driving the motor 1, the planetary gear 13 rotates
and abuts against the camera-front-panel-side stopper 56d. At that time,
the planetary gear 14 reaches the position P14A where the planetary gear
14 engages with the internal sector gear 7b provided in the stationary end
plate 7 of the camera body. Then, the planetary gear 14 is put into a
state in which the rotation thereof is stopped. When the planetary gear 14
is in this state, the clutch lever 20 is moved to the engaging position
P20A (see FIG. 3). Subsequently, when the pinion 1a of the motor 1 is
rotated counterclockwise, the planetary gear 14 tries to move
counterclockwise around the shaft of the gear 12, as viewed in FIG. 3.
However, the arm portion 20a of the clutch lever 20 is present on the
locus of this movement or revolution of the planetary gear 14 and abuts
against the planetary gear arm 13. Consequently, this arm portion 20a
hinders the counterclockwise revolution of the planetary gear 14.
Further, when the motor 1 is driven clockwise or counterclockwise as viewed
in FIG. 1 when the planetary gear 14 is in the aforementioned state, the
rotation of the carrier 5, the rotation of the planetary gear 6 around the
axis of rotation thereof itself, the revolution of the planetary gear 6
around the shaft of the gear 2b and the rotation of the carrier 2 cannot
be achieved, because the gear 12 cannot rotate at that time. As a
consequence, the rotation of the pinion 1a of the motor 1 is transmitted
to the gear 3 through the planetary gear 4. The motor 1 can rotate in both
directions, namely, can rotate clockwise and counterclockwise. Thus,
similarly, the bevel gear 31 secured to the screw shaft 32 can rotate in
both directions. Moreover, the lens barrel 34 can be caused to advance and
retreat in the direction of the optical axis. Thus, when being in the
state illustrated in FIG. 3, only the lens barrel 34 can be driven.
Next, operations of opening and closing the shutter in the lens barrel will
be described hereinafter.
When the lens barrel 34 is located at the collapsing position P34A, the
rotation of the rotation operation portion 38 for the arrow wheel 37 is
restricted by the camera-front-panel-side stopper portion 56f as shown in
FIG. 3, and the rotation operation portion 38 maintains a shutter closing
state. At that time, the clutch lever 20 is in the engaging position P20A.
Then, the motor 1 is rotated clockwise when the rotation of the aforesaid
planetary gear 14 illustrated in FIG. 3 is locked. Subsequently, the lens
barrel 34 moves in the direction of the arrow D1 of FIGS. 2 and 3. The
rotation operation portion 38 for the arrow wheel 37 moves in the same
direction D1 in such a manner as to be integral therewith. Then, the
rotation operation portion 38 is released from the stopper 56f. Further,
the rotation operation portion 38 is pushed leftwardly, as viewed in FIG.
3, namely, in a shutter opening direction at all times by the spring 47
for providing a drive force used to drive the shutter. However, because
the clutch lever 20 is in the engaging position P20A, a pushing force of
the closing spring 48, which is stronger than that of the aforesaid spring
47, acts on the shutter through the side surface of the arm portion 20c.
Thus, the shutter closing state is maintained. This state is also a
shutter open ready state in which an exposure is started immediately if
the clutch lever 20 retreats.
When the solenoid 27a is energized during this shutter open ready state,
the clutch lever 20 retreats to the evacuation position P20B. Thus, the
rotation operation portion 38 is released from the abutting state and is
then moved by the force of the spring 47 to the position P38B. This
movement of the rotation operation portion 38 causes the arrow wheel 37 to
rotate in a shutter opening direction. Then, the sector 39 is put into an
open state, and thus an exposure operation is performed. Incidentally, it
is sufficient for thereafter putting the shutter into a closed state to
deenergize the solenoid 27a. In response to the deenergization of the
solenoid 27a, the clutch lever 20 is returned again to the engaging
position P20A by the pushing force of the spring 27c or 48. Further, the
rotation operation portion 38 is pressed by the arm portion 20c, so that
the arrow wheel 37 is rotated in the shutter closing direction and thus
the shutter is returned to the closed state.
Next, a film feeding drive operation will be described hereinbelow.
When the motor 1 is driven in such a way as to cause the gear 12 to rotate
counterclockwise from the condition or position thereof illustrated in
FIG. 3, the clutch lever 20 is urged to the right as viewed in FIG. 3 by
the force of the closing spring 48 at all times. Thus, the planetary gear
14 cannot perform the revolution around the shaft of the gear 12. Namely,
the planetary gear 14 remains engaged with the internal gear 7b of the end
plate 7. Incidentally, referring to FIG. 4, there is shown a perspective
view of the differential gear mechanism and the film feeding mechanism,
which are in the aforesaid state illustrated in FIG. 3.
The moving core 27b of the plunger unit 27 is coupled to the aforesaid
clutch lever 20. When feeding electric current through the solenoid 27a,
the moving core 27b is attracted thereto. Further, the clutch lever 20
moves from the engaging position P20A to the evacuation position P20B.
When the clutch lever 20 moves to the evacuation position P20B and retreats
from the position on the locus of the revolution of the planetary gear 14,
the planetary gear arm 13 is put into a state in which the planetary arm
13 is not interfered by the arm portions 20a and 20b of the clutch lever
20. Subsequently, the sun gear portion 12b of the gear 12 is rotated
counterclockwise, as viewed in FIG. 3, during energizing of the solenoid
27a. Then, the planetary gear arm 13 turns to the position P13C at which
the planetary arm 13 abuts against the camera-front-panel-side stopper
56e. Thus, the planetary gear 14 engages with the gear 19. This gear 19
fixed to the winding shaft 50 of the film wind drive mechanism 25.
Incidentally, FIG. 5 shows a perspective view of the differential gear
mechanism and the film feeding mechanism while the aforesaid planetary
gear 14 engages with the gear 19 of the winding shaft 50.
If the sun gear portion 12b keeps rotating counterclockwise when the
aforesaid planetary gear arm 13 is in the aforementioned position P13C,
the gear 19 continues rotating anticlockwise. Further, the bevel gear 52a
is driven through the screw gear 50a of the winding shaft 50, so that the
spool shaft 52 is rotated. Thus, the operation of winding the film is
performed.
During the winding operation, torque is acted upon the fork shaft 53 of the
cartridge chamber through the film. As above described, the screw gear 51a
having been engaged with the bevel gear 53a is driven smoothly by the
aforesaid bevel gear 53a, so that the winding of the film is performed
without a hitch.
Further, it is necessary for rewinding the film to release the aforesaid
gear 14, which has been caught by the arm portion 20a of the clutch lever
20, from the engagement between the gear 14 and the portion 20a and then
engage the gear 14 with the spur gear 8.
Then, the moving core 27b is attracted by once energizing the solenoid 27a
so as to engage the gear 14 with the bevel gear 8. Subsequently, the sun
gear portion 12b of the gear 12 is rotated counterclockwise as viewed in
FIG. 3 during which time the clutch lever 20 is retreated from the locus
of the gear 14. Thus, the revolution of the gear 14 to the gear 8 is
performed. If the solenoid 27a is deenergized when the gear 14 approaches
the spur gear 8, the arm portion 20b of the clutch lever goes into the
locus of the revolution of the gear 14 and then abuts against the
planetary gear arm 13. Further, the gear 14 is in the position P14B, so
that the revolution thereof is prevented.
When the aforesaid planetary gear arm 13 is in the position P13B, the
planetary gear 14 engages with the spur gear 8. By keeping the sun gear
portion 12b rotating in this state, the drive force of the motor 1 is
transmitted from the sun gear portion 12b of the gear 12 to the spur gear
8 and the spur gear 18 provided on the rewinding shaft 51 through the
planetary gear 14. Incidentally, in this case, the aforesaid gear 8 is
driven to rotate only counter clockwise as viewed in FIG. 3. Further, the
bevel gear 53a is rotated through the screw gear 51a. Moreover, the fork
shaft 53 is driven. Thus, the rewinding of the film is performed.
During the rewinding operation, the torque is acted upon the spool shaft 52
of the spool chamber through the film. However, as above stated, the screw
gear 50 having been engaged with the bevel gear 52a is driven smoothly by
the aforesaid bevel gear 52a, so that the rewinding is performed without a
hitch.
Next, an electric control circuit for the camera, which incorporates the
drive mechanisms of this embodiment, will be described by referring to a
schematic circuit diagram of FIG. 8 showing the electric control circuit.
The aforesaid electric control circuit has: a drive power source battery 70
for use mainly in a camera; a power supply stabilizing circuit 71 for
stabilizing a power supply voltage; a central processing unit (CPU) 72 for
performing a control operation of the camera; an interface circuit 73 for
sending and receiving signals among various control units, control
elements and CPU 72; and a drive circuit 74 for driving the aforesaid
motor 1 and the solenoid 27a of the plunger unit 27.
Moreover, a main switch 75 and a release switch 76 and a rewind switch 77
of the camera are connected to the aforesaid CPU 72. Furthermore, the
encoding patterns 43a, 43b and 43c provided on the encoder board 43 are
also connected to CPU 72. Additionally, the terminals of light emitting or
receiving elements of the photoreflectors 62 and 63 and the
photointerrupters 61 and 64 are connected to CPU 72 through the interface
circuit 73.
The aforesaid photoreflector 62 functions as a clutch and is operative to
judge whether or not the planetary gear arm 13 reaches the rewinding
position P13B. When this reflector is turned on, CPU 72 detects that the
planetary gear 14 engages with the spur gear 8 for rewinding. Further, the
photointerrupter 61 is used for detecting the rotation of the motor and is
operative to detect the rotation state of the motor 1 by sensing the
motion of the slit disk 1b which rotates between the light receiving and
emitting elements thereof. Thereby, the advanced and retreated positions
of the lens barrel 34 are controlled.
Photoreflector 63 is a sensing element for detecting film perforations and
is operative to count the film perforations when winding film. Further,
the photointerrupter 64 is provided in the lens barrel 34 and is operative
to detect the motion of the rotation operation portion 38 for the arrow
wheel 37. When this photointerrupter 64 is turned on, the open state of
the shutter is detected. Moreover, CPU 72 controls shutter timing.
Next, a sequence of steps of a photographing process of the camera, which
includes operations of the electric control circuit and the drive
mechanisms configured as above described, will be described hereinbelow by
referring to flowcharts of FIGS. 9 to 11, the electric circuit diagram of
FIG. 8 and the sectional diagrams of the mechanisms as illustrated in FIG.
1 to 3. Incidentally, in the following description, the clockwise
direction when viewed from the pinion side of the motor 1 is referred to
as the direction of a normal rotation; and the counterclockwise direction
when viewed from the pinion side of the motor 1 is referred to as the
direction of a reverse rotation.
FIG. 9 is a flowchart of a program for performing a sequence of steps of an
ordinary photographing process of the camera. In this sequence, first, the
main switch 75 is turned on. Then, the voltage developed across the
battery 70 is supplied to each of the control elements through the
power-supply stabilizing circuit 72 in the camera. Thus, CPU 72, which has
been in a sleep state, starts up. Then, it is monitored (in step S101)
whether or not the release switch 76 is turned on.
If not, the program jumps to step S102 whereupon it is checked whether or
not the rewind switch 77 is turned on. If turned on, a rewind subroutine
of FIG. 10 (to be described later) is performed (in step S103) and thus a
photographing state is completed.
In contrast, if the release switch 76 is turned on, automatic focusing (AF)
operation is performed in steps S104 to S107. In the mechanisms, the motor
1 performs one-way rotation in the direction of a normal rotation. Such a
rotation of the motor 1 causes the planetary gear 4 to rotate, because the
carrier 2 cannot rotate at that time. Thus, the gear 3 is rotated.
Further, as a consequence, the screw shaft 32 is rotated. Finally, the
lens barrel 34 is caused to advance in the forward direction of the
optical axis O.
Thereafter, in step S105, it is monitored whether or not the AF trigger is
turned on. Namely, it is detected whether or not the armature 42b having
been electrically grounded at all times is electrically connected with the
pattern 43b. When the armature 42b is electrically connected therewith,
the program goes to step S106. This position, at which the electrical
connection of this armature therewith is detected, is used as a trigger
position for detecting the advanced position of the lens barrel 34 in AF
operation. Thence, the motor 1 keeps rotating, so that the lens barrel 34
is further advanced in the forward direction.
In the step S106, it is monitored whether or not pulse signals of a number
predetermined by CPU 72 from the aforesaid trigger position are outputted
from the photointerrupter (hereunder abbreviated as PI) 61 for detecting
the rotation of the motor 1. When the number of detected pulse signals is
matched with the predetermined number of pulse signals, it is judged that
the lens barrel 34 reaches the predetermined position for focusing. Thus,
an operation of driving and causing the motor 1 to rotate is stopped (in
step S107). In this state, the automatic focusing (AF) operation is
stopped. In the state in which the aforementioned
automatic-focusing-operation is completed, the rotation operation portion
38 for the arrow wheel 37 is in the position P38A', which is the shutter
closing position, because the portion 38 is placed in the lens barrel 34.
Then, if the plunger unit 27 is turned on in step S108, namely, if the
solenoid 27a is energized, the moving core 27b is attracted and the clutch
lever 20 moves against the pushing force of the closing spring 48
leftwardly, as viewed in FIG. 3, to the evacuation position P20B. On the
other hand, the rotation operation portion 38 is moved by the pushing
force of the spring 47 leftwardly, as viewed in this figure, to the
shutter opening position P38B. By this movement of the portion 38, the
sector 39 is released and the shutter is put into the opened state.
When performing this shutter opening operation, the photointerrupter of
FIG. 8 is linked with the movement of the rotation operation portion 38
and is turned on. Further, the aforesaid opened state of the shutter is
detected, so that a timing operation for automatic exposure is triggered.
Next, at step S109, it is monitored whether or not a shutter open time
reaches the length of a time period, which is predetermined by CPU 72.
After the elapse of the necessary shutter open time period, the plunger
unit 27 is turned off in step S110. Namely, the solenoid 27a is
deenergized.
In response to the deenergization of the aforesaid solenoid 27a, the clutch
lever 20 returns to the engaging position P20A in the initial condition
illustrated in FIG. 3. Then, the arm portion 20c presses and causes the
rotation operation portion 38 for the arrow wheel 37 to move. Thus, the
shutter is put into the closed state thereof. As a result of performing a
process composed of the aforesaid steps S108 to S110, the automatic
exposure (AE) operation is completed.
Upon completion of the aforementioned film exposure operation, the camera
moves the lens barrel 34 to the collapsing position P34A which is the
initial position thereof. Namely, when rotate the motor in the direction
of a reverse rotation, which is different from the aforementioned driving
direction, in step S111, the lens barrel 34 comes to retreat in the
direction of the optical axis O, because the carrier 2 does not rotate
similarly as in the aforementioned case.
Then, it is monitored in step S112 whether or not a collapsing switch is
turned on. Namely, it is monitored whether or not the armature 42c is off,
namely, disconnected from the pattern 43c. If off, it is judged that the
lens barrel 34 is located at the collapsing position P34A, and then the
motor 1 is stopped in step S113. Thus, a collapsing operation is finished.
Subsequently from the aforementioned collapsing operation, exposed film
needs winding up. Then, in step S114, the plunger unit 27 is turned on,
namely, the solenoid 27a is energized so that the clutch lever 20 is
retreated from the locus of the revolution of the planetary gear 14.
Further, in step S115, the motor 1 is reversed. This reverse drive
operation causes the planetary gear 14 to perform the counterclockwise
revolution as viewed in FIG. 3, and the planetary gear 14 comes to engage
with the gear 19 for driving the film wind drive mechanism 25.
When driving the aforesaid planetary gear 14, the gear 3 tries to rotate or
drive the lens barrel 34 to move from the collapsing position backwardly,
namely, to the direction of the advanced position along the optical axis
O. However, the lens barrel 34 is mechanically restrained from moving from
the collapsing position to the advanced position thereof. Thus, the lens
barrel 34 remains stopped at the aforesaid collapsing position P34A.
Consequently, the gear 3 stops rotating. The rotation of the motor 1 is
transmitted only to the carrier 5. Further, the motor 1 drives the
planetary gear 14 through the sun gear portion 12b of the gear 12 to
perform the aforementioned revolution.
As a result of the aforementioned revolution, the aforesaid planetary gear
14 comes to engage with the gear 19. Further, for the purpose of insuring
the engagement between the gears 14 and 19, it is detected by the
photoreflector 62 for the clutch whether or not the planetary gear arm 13
securely moves during the revolution of the gear 14. To that end, in step
S116, it is monitored whether or not the reflecting plate 13a of the
planetary gear arm 13 passes through a position opposite to the
photoreflector 62, namely, whether or not the state of the photoreflector
62 is changed from an on-state to an off-state.
If it is detected in the aforementioned step S116 the state of the
photoreflector 62 is changed from the on-state to the off-state, the
rotation of the motor 1 is maintained for a certain constant time period
in step S117. Thus, it is monitored whether or not this predetermined
constant time period has passed. If passed, the rotation of the motor 1 is
stopped once in step S118.
Then, in step S119, the motor 1 is further reversed. Moreover, when the
gears 14 and 19 are engaged with each other, an operation of winding the
film is commenced. Furthermore, in step S120, the solenoid 27a of the
plunger 27 is deenergized. The clutch lever 20 is returned to the initial
engaging position P20A. Subsequently, in step S121, a subroutine for
one-frame advance of the film is executed. Upon completion of this
one-frame advance, the motor 1 is stopped in step S122.
When the aforementioned operation of winding the film is completed, the
solenoid 27a of the plunger 27 is energized in step S123 so as to return
the camera to the initial state. Thus, the clutch lever 20 is retreated
again from the position on the locus of the aforesaid revolution of the
gear 14.
Subsequently, in step S124, the motor 1 is caused to perform normal
rotation. At that time, the gear 3 tries to rotate. However, a load put on
the driven system connected posterior to the gear 12 is smaller than the
load put on the lens barrel drive system. Thus, by the action of the
aforesaid differential gear, the lens barrel drive system is not driven.
Furthermore, the drive force of the motor 1 is transmitted from the side
of the carrier 5 to the gear 12.
When the sun gear portion 12b of the gear 12 is driven clockwise owing to
the rotation of the carrier 5, the planetary gear 14 starts the
aforementioned revolution and thus comes to engage with the sector gear
7b. Simultaneously with this, the planetary gear arm 13 abuts against the
stopper 56d. During this time, for the purpose of checking whether this
revolution is securely performed, it is monitored whether or not the
reflecting plate 13a of the planetary gear arm 13 passes through a facing
position after the reflecting plate 13a of the planetary gear arm 13 faces
the photoreflector 62 for the clutch at the facing position. Namely, in
step S125, it is monitored whether not the state of the photoreflector 62
is changed from the on-state to the off-state. If changed from the
on-state to the off-state, for the purpose of causing the gear 14 to
securely engage with the sector gear 7b, it is monitored in step S126
whether or not a predetermined time period has passed. After the lapse of
this predetermined time period, the motor 1 is stopped in step S127.
Thereafter, the solenoid 27a of the plunger 27 is deenergized in step S128.
Thus, the clutch lever 20 is returned to the initial engaging position
P20A. Consequently, the device is returned to the initial state. In step
S129, it is checked whether or not the main switch is turned off. If
turned off, the power supply for the camera is turned off. In contrast, if
not turned off, the program jumps to step S101 whereupon the device is put
into a state in which the device waits for the turning-on of the release
switch 76.
Next, a subroutine for performing a film rewinding operation will be
described hereunder by referring to the flowchart of FIG. 10.
During performing the sequence of steps of the photographing process in
FIG. 9, if it is detected in step S102 that the rewind switch 77 (see FIG.
8) is turned on, the subroutine illustrated in FIG. 10 is called. Then,
the film rewinding operation is performed.
Namely, in step S201, the solenoid 27a of the plunger unit 27 is energized,
so that the clutch lever 20 is retreated from a position on the locus of
the aforementioned revolution of the planetary gear 14. Then, if the motor
1 is reversed in step S202, the planetary gear 14 performs the
counterclockwise revolution. Further, the reflecting plate 13a of the
planetary gear arm 13 reaches the facing position at which the plate 13a
faces the photoreflector 62, the photoreflector 62 is turned on. This
state is monitored in step S203. Subsequently, the motor 1 is stopped in
step S204. Simultaneously, the solenoid 27a of the plunger unit is
deenergized in step S205, the clutch lever 20 is returned to the initial
engaging position P20A.
As a result of the return of the clutch lever 20, the planetary gear arm 13
is placed between the arm portions 20a and 20b of the clutch lever 20.
Subsequently, if the motor 1 is reversed in step S206, the planetary gear
arm 13 is placed at the position P13B, at which time the planetary arm 13
abuts against the arm portion 20b of the clutch lever 20, owing to the
aforementioned counterclockwise revolution of the gear 14. In this state,
the planetary gear 14 engages with the spur gear 8 that has been engaged
with the spur gear 18 for driving the film rewind drive mechanism 26.
Therefore, the film winding operation is continued by causing the motor 1
to keep rotating around the axis thereof.
In step S207, it is monitored by CPU 72 whether or not the rewinding
operation is completed. When completed, the motor 1 is stopped in step
S208. Thereafter, in order to return the camera to the initial state or
condition, a clutch reset operation of resetting the planetary gear arm 13
is performed in step S209. This clutch reset operation is the same as a
process composed of steps S123 to S128 of the aforesaid flowchart of FIG.
9. After this reset operation, the photographing process by the camera,
which is composed of the sequence of the aforementioned steps, is finished
by putting the main switch of the camera into a state being equivalent to
a state in which the main switch is turned off.
Next, a subroutine for a film end detection operation, which is performed
when failing to wind one frame of the film in the middle of the film
winding operation and thus suspending the film winding operation, will be
described hereinbelow by referring to the flowchart of FIG. 11.
Incidentally, this film end detection operation is performed by executing
this subroutine in the one-frame advance operation corresponding to the
aforementioned subroutine called in step S121 of FIG. 9.
First, in step S301, an output of the photoreflector 63 is monitored so as
to observe whether or not the film is normally fed, by detecting a
perforation of the film. If there is no pulse output corresponding to the
movement of a film perforation within a predetermined time period, it is
judged that the film end is reached or that the film stops halfway through
a film feeding operation. If no change occurs in the aforesaid pulse
output within a predetermined time period, the motor 1 is stopped in step
S302.
Thereafter, the film should be rewound. To that end, it is necessary to
return the planetary gear arm 13 to the initial state. Thus, an operation
similar to the reset operation by the planetary gear arm 13 in step S209
of FIG. 10 for returning the camera to the initial state, namely, the same
operation as composed of steps S123 to S128 of FIG. 9 is performed in a
clutch reset process of step S303. Then, the rewinding operation is
performed in step S304 by executing the aforementioned subroutine of FIG.
10. Subsequently, the photographing process by the camera, which is
composed of the sequence of the aforementioned steps, is finished by
putting the main switch of the camera into a state being equivalent to a
state in which the main switch is turned off.
As above stated, in the case of the film drive device for a camera, namely,
in the case of this embodiment, a rod-like shaft, on which a spur gear of
the film drive mechanism is mounted, is applied thereto and further, this
shaft is disposed therein by being inclined. Thus, the efficient placement
of the composing elements of the device is realized. Moreover, the
flexibility in placement of the composing elements is increased.
Furthermore, by employing a drive mechanism, which is obtained by the
combination of screw gears and bevel gears, as a drive force transmission
gear for transmitting a drive force to a spool shaft or a fork shaft
engaging with a cartridge, an operation of winding or rewinding the film
is achieved without canceling the engagement between the screw gear and
the bevel gear driven by the film at the time of winding or rewinding
film. Consequently, the configuration of a mechanism portion is
simplified. Moreover, a space occupied by the mechanism portion is
decreased. Furthermore, the flexibility in designing the mechanism is
increased. As a result, this invention is advantageous in reducing the
size and weight of a camera.
Moreover, the cost of a camera is reduced. In addition, the present
invention provides a film drive mechanism for a camera, by which a
reliable and secure drive operation is obtained.
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